低渗复合气藏斜井非达西渗流试井分析  

Well test analysis of inclined wells in the low-permeability composite gas reservoir considering the non-Darcy flow

作　　者：伍锐东 张春光 杨志兴 石美雪 姜瑞忠[2] WU Ruidong;ZHANG Chunguang;YANG Zhixing;SHI Meixue;JIANG Ruizhong(Shanghai Branch of CNOOC,Shanghai 200335,China;School of Petroleum Engineering,China University of Petroleum(East China),Qingdao,Shandong 266580,China)

机构地区：[1]中海石油(中国)有限公司上海分公司,上海200335 [2]中国石油大学(华东)石油工程学院,山东青岛266580

出　　处：《东北石油大学学报》2021年第6期111-120,I0007,I0008,共12页Journal of Northeast Petroleum University

基　　金：国家科技重大专项(2016ZX05027-004-004);中国海洋石油集团有限责任公司科技项目(CNOOC-KJ 135ZDXM39SH03)。

摘　　要：应用传统试井解释方法无法综合考虑低渗复合气藏非达西渗流和应力敏感性特征,难以获取真实储层参数。分析低渗气藏非达西渗流和应力敏感性的微观机理,完善渗流运动方程,建立内区常规、外区低渗的复合气藏斜井渗流数学模型;采用有限元方法进行Matlab编程求解渗流数学模型,选取等价压力点研究斜井压力分布;绘制井底压力动态曲线,根据曲线特征划分流动阶段,并进行参数敏感性分析;应用非达西模型进行试井解释,并与常规方法对比,检验模型的先进性。结果表明:非达西渗流使井底拟压力动态曲线后期逐渐发生上翘,非线性增强导致上翘幅度增大;井斜角大于60°后逐渐出现早期垂向径向流和中期线性流;内区半径减小导致内区拟径向流的持续时间缩短;内外区导压系数比影响内外区拟径向流过渡阶段拟压力导数曲线的斜率。考虑低渗复合气藏的渗流特性可提高试井压力曲线的拟合程度,解决储层参数多解性强的问题。该结果为低渗复合气藏的开发及斜井压力动态评估提供指导。For low-permeability composite gas reservoirs,the application of traditional well test interpretation methods can’t comprehensively consider the characteristics of the non-Darcy flow and stress sensitivity,which makes it difficult to obtain real reservoir parameters.Based on the micro-mechanism analysis of non-Darcy flow and stress sensitivity in low-permeability gas reservoirs,the flow motion equation was improved,thus the mathematical model of the inclined well in the composite gas reservoir with conventional inner zone and low-permeability outer zone was established.The finite element method was applied to solve the flow model by Matlab programming,and the equivalent pressure point was selected to study the pressure distribution of the inclined well.On this basis,the bottom hole pressure dynamic curve was drawn,flow stages are divided according to curve characteristics and the parameter sensitivity analysis was carried.Finally,the model was applied to the well test interpretation and the advanced nature of the model was confirmed by comparison with conventional methods.The results show that the non-Darcy flow can cause the gradual upward warping of the bottom hole pressure dynamic curve in the later stage and the non-linear enhancement leads to an increase in the upturn.When the inclination angle greater than 60°,the early vertical radial flow and the mid-term linear flow gradually appear.The decrease in the radius of the inner zone leads to a shorter duration of the pseudo-radial flow in the inner zone.The ratio of the conduction coefficients of the inner and outer zones affects the slope of the pseudopressure derivative curve in the transition phase of pseudo-radial flow in the inner and outer zones.Comprehensive consideration of the flow characteristics in the low-permeability composite gas reservoir can improve the fitting degree of the pressure curves.It can also solve the problem of strong diversification of reservoir parameters,which has guiding significance for the development of such gas reservoirs

关 键 词：低渗复合气藏 斜井 非达西渗流 应力敏感 有限元方法 试井分析 

分 类 号：TE348[石油与天然气工程—油气田开发工程]